JP2006078062A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger having a small-sized and inexpensive leak detecting structure while ensuring a high heat exchange efficiency. <P>SOLUTION: The heat exchanger 1X comprises a triple tube 1, and the triple tube 1 includes a middle tube 3 substantially concentric with an inner tube 2 and containing the inner tube 2, and an outer tube substantially concentric with the middle tube 3 and containing the inner tube 3. In the triple tube 1, only the middle tube 3 is formed of a dissimilar tube having continuous irregularities 5 and projections 6 on both inner and outer walls of a circular tube. According to this, since a plurality of small grooves 7 and a plurality of passages 8 which form the leak detecting structure can be formed in the middle tube 3 by forming the small grooves 7 with the inner tube 2 by the continuous irregularities 5 partially closely fitted to the inner tube 2, and the plurality of passages 8 with the outer tube 4 by the projections 6 closely fitted to the outer tube 4, the number of dissimilar tubes with high unit cost, which are needed to form the small grooves 7 and the passages 8, can be reduced to one while ensuring a sufficient heat transfer area between fluids to obtain a high heat exchange efficiency. Consequently, a heat exchanger having a small-sized and inexpensive leak detecting structure while ensuring a high heat exchange efficiency can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat exchanger for a liquid and a refrigerant in a heat pump type hot water heater, an air conditioner for home use, and for business use.

  In recent years, as the awareness of the global environment has increased, heat pump water heaters using carbon dioxide, a natural refrigerant, have been released in the hot water heater market. Due to the high-temperature and high-pressure and supercritical refrigerant characteristics of carbon dioxide, various types of heat exchangers for hot water supply different from conventional ones have been proposed and adopted. Moreover, the heat exchanger for hot water supply needs a structure in which water and the refrigerant are not mixed even when the pipe is corroded.

  Hereinafter, a conventional water heat exchanger for a heat pump type water heater using carbon dioxide will be described with reference to the drawings.

  FIG. 7 is a schematic configuration diagram of a conventional heat exchanger described in Patent Document 1. As shown in FIG. 7, a conventional heat exchanger 100 includes a copper flat tube 101 in which water flows inside, and a flat multi-hole tube 102 in which a CO 2 refrigerant flows inside aluminum, and the flat tube 101 Heat that suppresses an increase in the size of the refrigerant tube while ensuring a pressure resistant strength against high-pressure CO 2 refrigerant by the flat multi-hole tube 102 in a configuration in which the flat surface with the flat multi-hole tube 102 is spirally wound. It is an exchanger.

  The operation of the heat exchanger configured as described above will be described below.

Usually, the flat tube 101 and the tube 102, or the flat tube 101 and the flat multi-hole tube 102 exchange heat and warm low-temperature water with heat from a high-temperature refrigerant. Further, even when either one of them is corroded and a hole is formed, the refrigerant pipe and the water pipe are configured as independent pipes, so that foreign matters are not mixed into the water and leakage can be detected.
JP 2002-107069 A

  However, in the configuration of the conventional heat exchanger 100 described above, the flat tubes 101 and the flat multi-hole tubes 102 are alternately stacked. Therefore, to increase the heat exchange efficiency, the number of turns is increased to increase the heat transfer area. In order to reduce the thermal resistance of the flat contact surface between the flat tube 101 and the flat multi-hole tube 102, it is necessary to apply pressure by applying external pressure, and there is a problem that downsizing is limited.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a heat exchanger having a leak detection structure that is high in heat exchange efficiency, small, and inexpensive.

  In order to solve the above-described conventional problems, a heat exchanger according to the present invention includes an inner tube in which a fluid A flows, an inner tube that is substantially coaxial with the inner tube and includes the inner tube, A triple pipe comprising an outer pipe in which the fluid B flows between the inner pipe and the inner pipe, the inner pipe being partially in close contact with the inner pipe. It has an inner wall and an outer wall that is partially in close contact with the outer tube.

  Thus, by forming a triple tube in which three tubes are integrated, the thermal resistance between the fluid A and the fluid B is low, and a sufficient heat transfer area can be secured. Furthermore, by making the inner tube an unusual tube on both the inner and outer walls, a small groove is formed between the inner tube and a plurality of flow paths for fluid B between the outer tube and the odd tube in the triple tube. If the number is the smallest and both the small groove and the flow path of the fluid B are obtained, and the inner pipe or the middle pipe is corroded, before the progress of the corrosion reaches the respective flow paths of the fluid A or the fluid B, Corroded pipe-side fluid leaks from the small groove, and leakage can be detected. Moreover, the flow path of the fluid B can be ensured, and in addition, the fluid diameter can be reduced to increase the heat transfer coefficient of the fluid B, and the heat exchange efficiency can be increased.

  The heat exchanger of the present invention has a low thermal resistance between the fluid A and the fluid B, and can secure a sufficient heat transfer area to obtain a high heat exchange efficiency. In addition, since both the small groove and the flow path of the fluid B, which form the leakage detection structure, can be obtained with a single irregular pipe, the number of irregular pipes with high unit prices can be minimized, so that the cost increase due to the irregular pipe can be minimized. Can do. Therefore, it is possible to obtain a heat exchanger having a small and inexpensive leak detection structure with high heat exchange efficiency.

  The invention described in claim 1 includes an inner tube in which fluid A flows, an inner tube that is substantially coaxial with the inner tube and includes the inner tube therein, and an inner tube that is substantially coaxial with the inner tube and internally disposed therein. A triple pipe comprising a pipe and an outer pipe through which fluid B flows between the inner pipe, the inner pipe partially contacting the inner pipe, and a partial pipe on the outer pipe It has an outer wall that adheres closely to the surface. Thereby, the thermal resistance between the fluid A and the fluid B is also low, and a sufficient heat transfer area can be ensured to obtain high heat exchange efficiency. Furthermore, by making the inner tube an atypical tube on both the inner and outer walls, a small groove is formed between the inner tube and a plurality of flow paths for the fluid B between the outer tube and the number of the atypical tubes is the minimum number. In the book, both the small groove and the flow path of the fluid B are obtained. When the inner pipe or the middle pipe corrodes, the small groove has a leakage detection structure in which the fluid in the pipe on the corroded pipe side leaks before the progress of the corrosion reaches the respective flow paths of the fluid A or the fluid B. The outer wall partially in close contact with the outer tube of the tube secures the flow path of the fluid B. In addition, the fluid diameter can be reduced to increase the heat transfer coefficient of the fluid B, and the heat exchange efficiency can be increased. Furthermore, by increasing the number of atypical pipes with a high unit price, an increase in cost due to the atypical pipes can be suppressed. Therefore, it is possible to obtain a heat exchanger having a small and inexpensive leak detection structure with high heat exchange efficiency.

  According to a second aspect of the present invention, in the first aspect of the invention, the middle tube has a concavo-convex continuous on the inner wall and a protrusion on the outer wall. By closely contacting, a small groove that becomes a leak detection structure is uniformly formed on the outer periphery of the inner tube, and it is possible to realize high heat conduction between the inner tube and the middle tube by partially contacting closely. Further, since the protrusion on the outer wall is in close contact with the outer tube, the flow path of fluid B can be formed by securing the flow path of fluid B. Therefore, a heat exchanger having a high heat exchange efficiency and a structure capable of reliably detecting leakage is obtained.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the intermediate tube has a peripheral wall in which concave portions and convex portions having a substantially uniform tube thickness are alternately continued. A leak detection structure can be obtained by forming a small groove by closely contacting the concave portion with the inner tube, and a fluid B channel is formed by the convex portion of the peripheral wall closely contacting the outer tube. Can be secured. Further, since the tube thickness of the middle tube is substantially uniform and there is no portion biased to the wall thickness, there is no extra tube wall thickness, and the middle tube can be reduced in weight.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein in the outer wall of the inner tube, the close contact portion of the inner wall of the intermediate tube is larger than the non-contact portion. Thereby, the thermal resistance of the contact surface between the inner tube and the inner tube can be reduced, and high heat conduction can be realized between the inner tube and the inner tube.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the inner wall of the intermediate tube that is partially adhered to the inner tube is substantially parallel to the tube axis direction. It extends. Thereby, when the pipe is corroded, the flow friction of the fluid A or the fluid B leaking through the small groove formed between the middle pipe and the inner pipe in a direction not substantially parallel to the pipe axis direction is spirally formed. Compared to a groove or the like, the leakage can be easily suppressed by minimizing the leakage and the leakage can be easily detected.

  The invention according to claim 6 is the water refrigerant for a heat pump water heater according to any one of claims 1 to 5, wherein the fluid A is water and the fluid B is carbon dioxide. High heat pump efficiency can be obtained by using it as a heat exchanger.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
1 is a perspective view of a main part of a heat exchanger according to Embodiment 1 of the present invention, FIG. 2 is a cross-sectional view of the main part perpendicular to the tube axis direction of the triple tube of the heat exchanger according to the same embodiment, FIG. These are sectional drawings of the pipe-axis direction of the heat exchanger in the embodiment. FIG. 4 is a cross-sectional view of the main part perpendicular to the tube axis direction of the triple tube of another heat exchanger in the same embodiment.

  1 to 3, the heat exchanger 1 </ b> X includes a triple pipe 1, and the triple pipe 1 includes an inner pipe 2 in which water flows and an inner pipe 2 that is substantially coaxial with the inner pipe 2 and has an inner pipe 2 inside. The pipe 3 and the middle pipe 3 are substantially coaxial and provided with the middle pipe 3 inside, and between the middle pipe 3, an outer pipe 4 in which carbon dioxide flows as a refrigerant. The inner tube 2 and the outer tube 4 are circular tubes. The middle tube 3 has an inner wall 3 a having continuous small irregularities 5 that are partially in close contact with the inner tube 2 and an outer wall 3 b having protrusions 6 that are in close contact with the outer tube 4. The continuous irregularities 5 are in close contact with the inner tube 2 to form a plurality of small grooves 7, and the protrusions 6 are in close contact with the outer tube 4 to form a plurality of flow paths 8 in which carbon dioxide flows between the outer tube 4. To do. Here, the contact portion of the inner wall 3a of the inner tube 3 in the outer wall 2b of the inner tube 2 is larger than the non-contact portion. A cap 9 is attached to the tube end of the triple tube 1, the inner tube 2 and the middle tube 3 are penetrated, and the tube end of the outer tube 4 is closed. The groove 10 in the cap 9 serves as a carbon dioxide entrance / exit. The small groove 7 extends to the outside of the cap 9 substantially parallel to the tube axis direction. The inner tube 2, the middle tube 3, and the outer tube 4 are made of copper having good corrosion resistance and thermal conductivity.

  The operation of the heat exchanger 1X configured as described above will be described below.

  Water flows inside the inner tube 2 of the triple tube 1, and carbon dioxide flows through a plurality of flow paths 6 between the middle tube 3 and the outer tube 4, and the inner tube 2 and the middle tube 3 that are partially adhered to each other. Water and carbon dioxide exchange heat through the tube wall.

  As described above, the heat exchanger 1X of the present embodiment is a triple tube 1 in which three tubes are integrated, so that the heat resistance between the fluid A and the fluid B is low, and a sufficient heat transfer area is obtained. And high heat exchange efficiency can be obtained.

  Further, the continuous irregularities 5 of the inner wall 3a of the inner tube 3 are in close contact with the inner tube 2 to form a plurality of small grooves 7 on the outer periphery of the inner tube 2, while being in close contact with the inner tube 2 and the inner tube 2. High heat conduction can be realized between the pipe 3 and the projections 6 of the outer wall 3b are in close contact with the outer pipe 4 to form a plurality of flow paths 8 through which carbon dioxide flows between the outer pipe 4 and Of the triple tubes 1, the atypical tube with a high unit price is a minimum number, and both the small groove 7 and the carbon dioxide channel 8 can be obtained. An increase in cost due to the irregular pipe can be minimized. Further, by making the contact portion of the inner wall 3a of the inner tube 3 in the outer wall 2a of the inner tube 2 larger than the non-contact portion, the thermal resistance of the contact surface between the inner tube 2 and the inner tube 3 is reduced, and high heat conduction is achieved. Can be realized. When the inner pipe 2 is corroded by water or the like, water leaks from the small groove 7 to the outside of the cap 9, and the leakage can be detected. Furthermore, since the small groove 7 extends substantially parallel to the tube axis direction, the flow friction of the water passing through the small groove 7 in a direction not substantially parallel to the tube axis direction is suppressed as much as possible to facilitate leakage, It makes it easy to detect leaks. Further, the projection 6 prevents the triple tube 1 from being deformed or crushed, and the carbon dioxide channel 8 can be secured. In addition, the fluid diameter of the flow path 8 can be reduced, the heat transfer coefficient of carbon dioxide can be increased, and the heat exchange efficiency can be increased. Therefore, it is possible to obtain a heat exchanger having a small and inexpensive leak detection structure with high heat exchange efficiency.

  In the present embodiment, an irregular tube is shown in which four protrusions 6 are erected on the outer wall 3b of the middle tube 3, and the flow channel 8 between the outer tube 4 is formed into a plurality of substantially rectangular channels in a ring shape. However, the same effect can be obtained by forming the flow path 8 between the outer pipe 4 and the outer pipe 4 as shown in FIG. 4 as a modified pipe that forms a flow path surrounded by a plurality of two circular arcs.

  In this embodiment, the inner tube 2, the middle tube 3, and the outer tube 4 are made of copper, but the same effect can be obtained with brass, SUS, or the like. The inner tube 2 in which water flows is preferably made of a material having good corrosion resistance (for example, copper, stainless steel), and the outer tube 4 in which the coolant flows, the diameter is large, and the wall thickness is thick, is preferably high strength, A material made of a material having good thermal conductivity (for example, an alloy such as copper or aluminum) is preferable.

  Moreover, high heat pump efficiency can be obtained by using the fluid A as water, the fluid B as carbon dioxide, and using the heat exchanger 1X as a water-refrigerant heat exchanger for a heat pump water heater.

  In the embodiment of the present invention, the fluid A is water and the fluid B is carbon dioxide. However, the present invention is not limited to this. Other high-pressure refrigerants such as R410A and R32 and water, or heat between the same fluid having a temperature difference. Even if it is used for replacement, the same effect is obtained.

(Embodiment 2)
FIG. 5 is a cross-sectional view of a main part perpendicular to the tube axis direction of the triple tube of the heat exchanger according to Embodiment 2 of the present invention. In addition, about the same structure as the above-mentioned embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  In FIG. 5, the intermediate tube 11 of the heat exchanger 1X has an irregular shape having peripheral walls 11A in which concave portions 11a and convex portions 11b having a substantially uniform tube thickness are alternately continuous and extend substantially parallel to the tube axis direction. It is a tube.

  In the intermediate tube 11, a small groove 7 is formed by the convex portion 11 b of the peripheral wall 11 </ b> A and the inner tube 2, and a flow path 8 is formed by the concave portion 11 a of the peripheral wall 11 </ b> A and the outer tube 4. Here, in the outer wall 2b of the inner tube 2, the contact portion of the peripheral wall 11A of the middle tube 11 is larger than the non-contact portion.

  As described above, in the heat exchanger 1X of the present embodiment, the intermediate tube 11 has the peripheral wall 11A in which the concave portions 11a and the convex portions 11b having a substantially uniform tube thickness are alternately arranged, whereby the concave portion 11a of the peripheral wall 11A. The convex portion 11b is in close contact with the inner tube 2 and the outer tube 4, thereby forming a small groove 7 and a carbon dioxide flow path 8. Among the triple tubes 1, the atypical tube having a high unit price is one of the minimum number. Thus, it is possible to obtain both the small groove 7 and the carbon dioxide flow path 8 serving as a leakage detection structure.

  Further, since the tube thickness of the intermediate tube 11 is substantially uniform and there is no biased portion, there is no portion with an excessive tube thickness, and the intermediate tube 11 can be reduced in weight. In addition, it has a substantially uniform tube thickness and is suitable for drawing, and when manufactured by drawing, manufacturing costs can be reduced compared to continuous casting.

  In the embodiment of the present invention, the concave portion 11a and the convex portion 11b on the peripheral wall are shown as continuous rectangles, but the present invention is not limited to this, and is not limited to this. The same effect can be obtained with various shapes such as (not shown).

  As described above, in the heat exchanger according to the present invention, among the triple pipes, the inner pipe is made of an unusual shape on both the inner and outer walls, so that the number of unusual shaped pipes with a high unit price is one and the number of leaks is detected. It is possible to obtain both the small groove as the structure and the flow path of the fluid B, to obtain a high heat exchange efficiency with a sufficient heat transfer area, and to suppress an increase in cost due to the deformed pipe. Since it is possible to obtain a heat exchanger having a high, small and inexpensive leakage detection structure, it can be applied to applications such as heat pump water heaters, domestic and commercial air conditioners, and fuel cells.

The principal part perspective view of the heat exchanger in Embodiment 1 of this invention Cross-sectional view of the main part perpendicular to the tube axis direction of the triple tube of the heat exchanger in the same embodiment Sectional drawing of the pipe-axis direction of the heat exchanger in the embodiment Sectional drawing perpendicular to the tube-axis direction of the triple tube of the other heat exchanger in the same embodiment Sectional drawing perpendicular | vertical to the pipe-axis direction of the triple tube of the heat exchanger in Embodiment 2 of this invention Sectional drawing perpendicular to the tube-axis direction of the triple tube of the other heat exchanger in the same embodiment Schematic configuration diagram of a conventional heat exchanger

Explanation of symbols

1X heat exchanger 1 triple pipe 2 inner pipe 2b outer wall of inner pipe 3, 11 inner pipe 3a inner wall of middle pipe 3b outer wall of middle pipe 4 outer pipe 5 continuous irregularities 6 projection 11A peripheral wall 11a concave 11b convex

Claims (6)

An inner tube in which fluid A flows, an inner tube that is substantially coaxial with the inner tube and includes the inner tube, and an inner tube that is substantially coaxial with the inner tube and includes the inner tube. A triple tube comprising an outer tube through which fluid B flows, wherein the middle tube has an inner wall that is partially in close contact with the inner tube and an outer wall that is partially in close contact with the outer tube. Heat exchanger. The heat exchanger according to claim 1, wherein the middle tube has a concavity and convexity continuous with the inner wall and a protrusion on the outer wall. The heat exchanger according to claim 1 or 2, wherein the intermediate tube has a peripheral wall in which concave portions and convex portions having a substantially uniform tube thickness are alternately continued. 4. The heat exchanger according to claim 1, wherein a contact portion of the inner wall of the inner tube is larger than a non-contact portion in the outer wall of the inner tube. 5. The heat exchanger according to claim 1, wherein an inner wall of the middle tube that is partially in close contact with the inner tube extends substantially parallel to a tube axis direction. The heat exchanger according to any one of claims 1 to 5, wherein the fluid A is water and the fluid B is carbon dioxide.

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